000
FXUS65 KBOU 130306
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
906 PM MDT Fri Apr 12 2024

.KEY MESSAGES...

- Warm and dry weekend, continuing into Monday, with elevated
  fire weather conditions.

- A windy weather system will bring snow showers to the mountains
  with rain showers likely on the plains late Monday into Tuesday.

- Cool and windy weather for the rest of the week. Occasional snow
  showers are expected in the mountains with a chance of showers
  on the plains, most likely still rain.

&&

.UPDATE...
Issued at 854 PM MDT Fri Apr 12 2024

Quiet evening across Colorado. Satellite imagery shows clouds
pushing in central Colorado with a few weak showers lingering
across the higher terrain. No changes needed to the current
forecast. Temperatures drop into the 40s and 50s across the lower
elevations and 20s/30s for the high country overnight.

&&

.SHORT TERM /Through Saturday/...
Issued at 215 PM MDT Fri Apr 12 2024

Warm and dry weather will continue into Saturday with an upper
level ridge dominating this forecast period.

Mid-level moisture has increased slightly this afternoon, but
subsidence near the axis of the ridge has limited the development
of any substantial cloud cover. A weak shortwave is still expected
to drift across the region later this evening into Saturday
morning, which should bring just enough moisture and lift for a
few showers across the higher elevations. Outside the increase in
cloud cover and some brief rain or snow showers this shouldn`t be
impactful.

The ridge is forecast to restrengthen again on Saturday, with weak
westerly flow developing through the day. Mid-level temperatures
may be a degree or two cooler, but the added downslope component
to the low-level flow will keep temperatures in the mid to upper
70s across the plains, perhaps peaking in the low 80s across the
far eastern plains. Models also show deeply mixed/inverted-V
soundings across the plains during the afternoon with hints of
weak convective showers. Have added a little bit more coverage of
PoPs tomorrow though most locations will be more likely to see
gusty outflow winds vs. any measurable precipitation.

&&

.LONG TERM /Saturday night through Friday/...
Issued at 345 PM MDT Fri Apr 12 2024

Models have upper ridging in place for the forecast area Saturday
into Sunday afternoon. By Sunday night, fairly strong southwesterly
flow aloft is progged. There is weak downward synoptic scale
energy according to the QG Omega fields Saturday night through
most of Sunday night. The airmass looks pretty dry into Monday
morning; certainly in the lower levels. The low level pressure and
wind fields point to fairly decent southerly surface winds across
the plains by Sunday afternoon.

An upper closed low is expected to move across Colorado Monday and
Monday night. The NAM is a bit quicker with the feature then the
rest of the models. The center of the closed low moves eastward
across southeastern Colorado, with most of the models showing the
surface low somewhere around the northeast corner of the state by
00Z Tuesday (late Monday afternoon). The result is that low level
upslope flow is not good for a decent snowfall over the plains.
There is pretty decent synoptic scale energy with the upper low
however.  For moisture with the upper low, there is a fairly deep
plug of moisture, albeit short lived from Monday afternoon into
Tuesday morning for the mountains, and mainly just between 06Z-18Z
Tuesday for the plains. There isn`t a bunch of CAPE progged with
the system, with just some minor amounts mainly in the mountains
Monday late day. Will go with 10-40% pops in the mountains early
Monday, then 70-90%s Monday afternoon into Tuesday morning. For
the plains, 30-70%s look good Monday evening into Mid day Tuesday.

For temperatures, Sunday is the warmest looking day, with lower
80s F over the plains a good bet. Monday`s highs cool off about 10
degrees F. Of note, there really isn`t a lot of cold air with the
upper low Monday into Tuesday, so snow will be relegated to the
mountains and high foothills, Monday night into Tuesday morning.

For the later days, Tuesday through Friday, models have increasing
northwesterly flow aloft behind the exiting upper low Tuesday into
Wednesday. By later Wednesday, continuing into through Friday,
the flow is zonal and quite strong with a jet maximum parked over
Colorado Wednesday evening well into Friday. The airmass cools
off somewhat Tuesday and Wednesday, then a more significant
cool down Thursday and Friday. For moisture, there is some
lingering Tuesday, with Tuesday night and Wednesday to be fairly
dry. Moisture increases a bit for the later half of the week. Will
leave as is.

&&

.AVIATION /00Z TAFS through 00Z Saturday/...
Issued at 606 PM MDT Fri Apr 12 2024

A very weak circulation remains off to the south early this
evening. This shouldn`t have much impact at the terminals. Winds
will stay light easterly, returning to drainage after midnight at
08-14 kts.

Saturday, winds transition to the west to northwest at 09-15 kts.
BJC may see a brief duration of slightly stronger winds Saturday
morning (13-15Z), Low coverage high-based showers are possible in
the afternoon which will carry the potential for variable gusty
winds from any passing or neaby showers.

&&

.FIRE WEATHER...
Issued at 215 PM MDT Fri Apr 12 2024

Locally elevated fire weather conditions will continue this
afternoon across the plains and portions of the foothills.
Current RH values are near 10-15% across most of the lower
elevations though winds are generally less than 20 mph.

Warm and dry conditions will continue tomorrow with elevated fire
weather conditions forecast yet again. The lower elevations should
again see humidity values fall to 10-15% with wind gusts just
below criteria. There may be some brief, locally critical fire
weather conditions over portions of the Pawnee National Grasslands
and across far southern Lincoln county. Did ponder highlights but
don`t think there will be enough wind.

There will be elevated fire weather conditions both Sunday and Monday
afternoons over the southern and eastern plains areas with
humidity levels in the teens both afternoons.  Wind gusts get into
the 20-30 mph for a few hours each afternoon. At this time, if
highlights are needed, the best time would be Monday afternoon.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

UPDATE...Mensch
SHORT TERM.....Hiris
LONG TERM......RJK
AVIATION...Mensch
FIRE WEATHER...Hiris/RJK